I think the only character you can unlock is Orchid. As far as spending money, the free character rotates each week. You are not paying to win. You are just buying characters that you want to play. If all you want to play is Jago, then you are set. If you want another character, then you need to either buy it or wait until it is free for a week.

Yeaaaaaah.... but I actually didn't download all the characters because I was new to the game, and now im feeling so desperate for a chance to unlock a character in order to have a diverse gameplay through characters, so no I didn't get that

Always download the free games. Heck, you don't even need to let the games install. Just do it so you get the license saying you have it. This way you own these games just incase you change your mindcraft and want to try them or even end up liking them.